Electric-arc-rupturing device.



PATENTED APR. 19,1904.

S. H. SHORT.-

ELECTRIG ARC RUPTURING DEVIGE.

APPLIOATION FILED FEB. 11, 1902.

N0 MODEL.

by 54 fw A5 Wl'iizesses:

UNITED STATES Iatented April 19, 1904.

PATENT ()FFIQE.

SIDNEY H. SHORT, OF LONDON, ENGLAND, ASSIGNOR TO WESTINGHOUSE ELECTRIC &MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

ELECTRlC-ARC-RUPTURING DEVICE.

SPECIFICATION forming part of Letters Patent N0. 757,782, dated April19, 1904. Application filed February 11, 1902. Serial No. 93,515.- (Nomodel.)

To aZZ whom it may concern.-

Be it known that I, SIDNEY H. SHORT, a citizen of the United States, anda resident of London, in the county of Middlesex, England, have inventedcertain new and useful Improvements in Electric-Arc-Rupturing Devices,of which the following is a specification.

This invention relates to devices adapted to rupture an electric arewhen formed between two points, such as the switch-contacts of acurrent-controller for electric motors; and it has for its object toprovide a magnetic blow-out arc-rupturing device which can'lbebroughtclose to the are without requiringfthe protection of externalinsulation. 4

In carrying out my invention I dispose the contact-points between whichthe arc will be formed between the bare pole-pieces of an electromagnet,preferably having an externally-closed magnetic circuit, thesepole-pieces being electrically insulated from the magnetr core, so thatwhen the arc is drawnout and lengthened by the flux of the electromagnetthe path of the arc cannot be shortened by its striking the pole-pieces.v 1 I The invention may be applied to a single or multiple contactblow-out device, the same, general features being present under bothconj-I ditions.

My invention is illustrated in the accompanying drawings, in whichFigure 1 is an elevation, partly sectional, of a single-contact blow-outapparatus constructed in accordance with my invention. Fig. 2 is asimilar view of a double-contact device of the same generalconstruction, and Fig. 3 is a detail View.

In the drawings, 1 represents a switch-shaft provided with acontrolling-handle 2 and having mounted upon it a sleeve 3, carrying oneor more segmental contact-pieces 4 4. The contact-segments are eachadapted to engage with a spring-contact 5, as shown. The parts 4 and 5represent the terminals of an electric circuit and between them the arcis formed, which it is the purpose of the present invention to rupture.When the contacts 4 and 5 are in engagement, the circuit is closed. Thepoint of contact between these parts or the point at which the arc is tobe formed is arranged centrally between the pole-sur'faces of anelectromagnet 6. This magnet may be energized by the current whose flowis to be interrupted by the switch. The magnet 6, as shown, is closedexternally by an iron bar or horseshoe-frame 7, the same being madesufficiently long to prevent an are ever forming between it and thecontact-points.

Each limb of the electromagnet 6 is hollowed out, as shown, and Withinthe hollow portion are inserted an insulating-washer9 and aninsulating-ring 10, the latter being screwed into place within thehollow portion of the limb, the limb and the ring being correspondinglyscrew-threaded for this purpose. Each pole-piece is then similarlyscrewed into place within the insulating-ring, the whole forming acompact and strong mechanical structure.

Other means of connection may be selectedas, for example, that ofscrewing the polel-pieces over a hub in the limbs, insulation beinginterposed, so as to cause an electrical :separation between thepole-piece and the rnagnet-limb.

Such being the general structure and arrangement of the parts, wheneveron breaking the electric circuit an arc is formed between'the contactelements 4: and 5, it is immediately drawn out by the powerful magneticflux between the pole-pieces and becomes attenuated, taking a longer andlonger path in its endeavor to embrace an increasing number of lines offorce until rupture takes place. When the electric circuit is broken inone direction, the are forms outwardly away from the segment; but shouldthe current be flowing in the other direction the arc is extendedbetween the axes of the coil and the contactsegment.

The foregoing relates more particularly to the structures shown in Figs.1 and 3.

In the arrangement illustrated in Fig. 2 I provide two contact segmentsand fingers between the poles of an electromagnet of similar characterto that above described; but I so arrange the elements that the magneticflux will pass through each contact-segment in the same direction, thisbeing brought about by a suitable arrangement of the electricalconnections of the segments and contact-fingers. Thus in the arrangementillustrated I employ three energizing-coils, one arranged between thetwo sets of contact-points and one on the outside of each set. Themagnetic circuit of the two end coils is externally completed by anoutside iron bar or horseshoe-frame as before, While the intermediatecoil practically surrounds the double pole-piece formed in two parts,insulated from each other, and preferably connected in substantially thesame manher as has already been described in connection with eachpole-piece and its corresponding magnet-limb in Fig. 1. The pole-piecesat the ends are also insulated from the magnet-core, as alreadydescribed, and for the sake of mechanical strength they are connected inthe manner already indicated.

The whole structure illustrated in Fig. 2 forms, therefore, anelectromagnet with three coils and two air-gaps, the contact-pointsbeing disposed within these air-gaps, so that ares formed at thecontact-points will be blown out, as already described.

The number of sets of contacts and the number of magnet-coils may bemultiplied at will, provided the same general arrangement is followed asindicated in Fig. 2.

By virtue of the arrangements described herein it is possible to let themagnet-poles approach the point at which the are is to be formed quiteclosely without requiring that the pole-pieces shall be externallyinsulated and without any shortening of the path of the are through itsstriking the pole-pieces.

I claim as my invention 1. In an electric-arc-rupturing device, thecombination with the contact-points between which an arc is likely to beformed, of a polepieee in proximity to the arcing-point, the saidpole-piece being insulated from the limb of the magnet to which it isattached.

2. In an electric-arc-rupturing device, the combination with thecontact-pieces between which an arc is likely to be formed, of anelectromagnet having a pole-piece in proximity to the arcing-point, thesaid pole-piece being connected to the limb of the magnet but in sulatedtherefrom.

3. In an electric-arc-rupturing device, the combination with contactsbetween which the are is likely to be formed, of an electromagnet havinga bare pole-piece in proximity to the arcing-point, the said pole-piecebeing connected to the limb of the magnet but SOP- rated therefrom bysuitable insulation.

4. In an electric-arc-rupturing device, the combination with one or moresets of contacts between which an are or arcs is or are likely to beformed, of electromagnetic pole-pieces on opposite sides of each set,the said polepieees being arranged in proximity to the are ing point orpoints and being safely insulated at points behind their faces, as andfor the purpose set forth.

Signed at London, in the county of Middlesex, England, this 31st day ofJanuary, A. l).

SIDNEY vH. SHORT. Witnesses:

H. l). JAumsoN, A. NUTTING.

